noun
A commercial establishment where customers play mahjong, often for money. Synonymous with 雀荘 (jansō), but 麻雀屋 is a more colloquial term.
See also: 雀荘
駅前の麻雀屋で友達と半荘打った。
I played a hanchan with friends at the mahjong parlor in front of the station.
雀荘 is the more formal or industry term for a mahjong parlor, while 麻雀屋 is a common, slightly more casual way to refer to such establishments.
Compound of 麻雀 (mājan, 'mahjong') + 屋 (ya, 'shop'). The reading マージャン is a direct borrowing from Chinese 麻將 (májiàng).